From: Yuri Khan <yurivkhan@gmail.com>
To: van@scratch.space
Cc: help-gnu-emacs <help-gnu-emacs@gnu.org>
Subject: Re: DocView resolution for PDF on WQHD
Date: Tue, 19 Jun 2018 15:13:24 +0700 [thread overview]
Message-ID: <CAP_d_8WKNUP5R1cPPeSJpZi+U2kqK5LSVHHC-eUyoWVdWW+0YA@mail.gmail.com> (raw)
In-Reply-To: <EFF327D8-6F27-4685-99F9-D64E4F72204D@scratch.space>
On Tue, Jun 19, 2018 at 11:29 AM Van L <van@scratch.space> wrote:
> At about the time when src/macfont.h entered the source code I first experienced PDF viewing inside NetBSD GNU Emacs and was blown away by the crispness. I suppose HiDPI is a 4k, 5k, 8k display.
It’s not that simple. There are many factors in play.
First, there is the pixel count. This is what WQHD, 4k, 5k, 8k, and
explicitly stated pixel counts such as 2560×1440 refer to.
Second, there is the screen diagonal or screen size, usually expressed
in inches.
Given a pixel count and a diagonal, one can calculate the linear pixel
density: ld = sqrt(w^2 + h^2) / diag.
Third, there is the eye to screen distance, which can be measured in
meters, feet, or arm’s lengths. A desktop monitor is normally one
arm’s length (≈70cm) from the eye; a laptop, tablet, or phone screen
is usually at about half that distance; and a cinema screen might be
as far as twenty meters away.
Given a linear pixel density and eye to screen distance, one can
approximate the angular pixel density: ad = ld / dist.
Perceived crispness of the image, and what HiDPI is really about, is a
function of the angular pixel density.
A typical desktop monitor is about 100 dpi at arm’s length. A HiDPI
monitor is about 200 dpi at arm’s length.
next prev parent reply other threads:[~2018-06-19 8:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-18 9:10 DocView resolution for PDF on WQHD Van L
2018-06-18 9:26 ` Alexis
2018-06-18 12:53 ` Van L
2018-06-18 14:30 ` Yuri Khan
2018-06-18 15:26 ` Van L
2018-06-18 16:06 ` Yuri Khan
2018-06-19 4:29 ` Van L
2018-06-19 8:13 ` Yuri Khan [this message]
2018-06-19 10:24 ` Van L
2018-06-19 13:26 ` Van L
2018-06-22 16:14 ` Van L
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